Grenade fuse tester fixture



Nov. 12, 1957 F. J. CURRAN 2,812,655

GRENADE FUSE TESTER FIXTURE Filed June 22. 1955 INVENTOR.

United fitates Patent Office 2,812,655 Patented Nov. 12, 1957 GRENADEFUSE TESTER FIXTURE Frank J. Curran, Downers Grove, Ill. ApplicationJune 22, 1955, Serial No. 517,249 4 Claims. (Cl. 73-35) The presentinvention relates generally to a hand grenade fuse, but moreparticularly to a simple, inexpensive and long-lasting grenade fusetester fixture which will withstand the explosion or blast hundreds oftimes over the fixtures heretofore used.

It has been the practice heretofore in the manufacture of fuses for handgrenades to make a certain percentage of fuse tests in relation to thenumber of fuses manufactured and in this connection, sleeves which wererequired to embrace the fuse in these tests were made from pipe, cut offand machined to the correct length, thereby requiring toolmakers timeand other labor and in addition required continuous replacements, all ofwhich added up to excessive cost and expense to supply these sleeves andmake these tests. The sleeve in these instances supports the fusetherein and surrounds the detonator of the fuse so as to completelyconfine the explosion on impact when the supporting sleeve and fuse isdropped for the test. In this connection, the blast or explosion causedby these tests would blow out and destroy the sleeves after two or threetests, requiring replaced machined sleeves, which entailed considerableexpense.

It is, therefore, one of the primary objects of the present invention tonot only overcome the disadvantages above pointed out, but to alsoprovide an improved fuse testing fixture which will partly confine theblast of the explosion but permit the major portion of the explosion orblast to blow out between spaced apart studs or screws mounted insuitably spaced apart apertures in the test member. With the presentinvention, when necessary, new conventional screws or studs which arereadily available, may be quickly substituted for the old ones by theoperator without the loss of time or the use of a toolmaker to furnishthe replaced part. The screws or studs of the present invention surroundthe detonator of the fuse and guide the positioning of the fuse inmounting the same in the supporting structure.

A further object of the invention is to provide a novel and improvedfuse testing fixture which not only provides an economical and easy wayto replace the mutilated parts, but also provides commercially availablereplacement parts which can be purchased at a low cost in comparisonwith the cost of machined pipe sleeves.

A still further object of the invention is to provide a novel andimproved construction of a fuse testing drop fixture in whichreplaceable sets of screws or studs can withstand approximately from 250to 300 tests, after which the worn out or damaged screws or studs can bereadily replaced by new ones.

A still further object of the invention is to provide a fuse testingdrop fixture in which the body thereof is provided with additional setsof apertures in the fixture member so that the screws or studs may beplaced in these new apertures if for any reason the previously usedholes in the fixture are mutilated.

These and other objects are accomplished by providing a construction andan arrangement of the various parts in the manner hereinafter describedpointed out in the appended claims.

Referring to the drawings:

Fig. 1 is a side elevation view of my improved dro test fixture for handgrenade fuses showing the manner in which the same is supported in agrenade fuse testing machine or device;

Fig. 2 is a cross sectional View taken on the line 2--2 in Fig. 1; and

Fig; 3 is a top plan view of the same.

In order to disclose a more complete understanding of my improvedgrenade fuse testing fixture, I have shown the same in connection with aconventional fuse testing machine or device, only a fragmentaryportion'of which is shown in the drawings, for supporting the fuse andthe fuse testing fixture in position in the device and the means forwithdrawing the pin and releasing the lever synchronously with droppingthe fuse and fuse fixture.

and particularly This conventional fuse testing machine comprisesbriefly, a main frame member 10, which is supported on a base or stand(not shown). Secured to an extended portion 11 of the main frame 16 is acup-shaped member 12. This cup 12 is cylindrical in shape and is adaptedto support centrally therein my improved fixture and the attache-d fuseas clearly shown in Figs. 1, 2 and 3 of the drawings. This cup 12 has avertically extending slot in the side wall thereof, as shown at 13, forthe accommodation of a cap lever of the fuse in the manner hereinafterdescribed. My improved fixture is supported in the cup 12 by areciprocable trigger member 14 which has its outer edge conicallycurved, as shown at 15, to engage the conical surface of my improvedfixture. The device 10 is provided With a fuse pin pulling member 16which is provided with a hook, as shown at 17, on the outer end thereofto engage the ring of the fuse. The trigger member 14 and the pullermember iii are electrically actuated through a solenoid and controlledby a micro switch (not shown) so that they can be controlled at a remotedistance from the device as a whole in the manner well understood in theart.

My improved fuse testing fixture comprises a member in the form of afrustum of a cone, generally indicated by the reference character 12%.The member in has a conical surface, as shown at 19, which terminates ina fiat bottom 2a. The conical surface 18 terminates in a relativelyshort cylindrical portion 21 which fits loosely into the circular recessof the cup 3.2, the upper portion of the member 18 and the flat top 21.The member 18 is also provided with a centrally located conical recess22. This recess 2.2 terminates in an axially threaded bore 23 in whichthe fuse is adapted to be mounted therein in threaded engagement. Thetop surface 21 of the fixture member 1'8 is provided with a set ofvertically dispose-d equally spaced apart threaded bores 24. 0nd set ofsimilarly equally spaced apart threaded bores 25 are provided in themember 18 which are adapted to have mounted therein threaded screws 2aThe threaded apertures 24 are spaced apart approximately one hundredtwenty degrees fro-m each other and the threaded apertures 25 aresimilarly spaced apart, but each of these sets of apertures are spacedrelatively a slight distance from one another as clearly shown in Fig. 3of the drawings. The purpose of this arrangement is to permit threethreaded screws to be equally spaced so that the periphery or head ofthe screws engage the inner wall of the cup in a relatively loosefashion for maintaining and guiding the fixture in position, prior toreleasing it from the device. It is also a further advantage of thesespaced apart screws to partially confine the explosive blast at the sametime permit the major portion of the blast or explosion to freely passbetween the upright screws A secand thereby reduce to a minimum thedestructive effect both on the fixture 18 and the screws. Should theblast distort the screws, a replaced one may be inserted in threadedengagement with the fixture 18 with a minimum effort or expense. Theaddition of threaded apertures in the fixture 18 permits their use inthe event that threads of a previous usedaperture has become mutilatedso that the fixture can be continued to be used for additional tests.

The grenade fuse here shown is of a conventional type and comprises ahead 27 provided with externally threaded studs 28 formed integrallytherewith which is adapted to be mounted in threaded engagement with thethreaded aperture 23 of :the fixture 18. Formed integrally with the stud23 is a sleeve extension 29. Mounted in the sleeve 29 is a detonatormember 30. Pivotally and removably mounted on two laterally extendingpinlike lugs 31 formed integrally with the head 27 is a conventionalquick detachable release lever 32. The release lever 32 is retained inposition on the head 27 by a removable cotter pin 33 which extendsthrough aligned apertures in the parallel and oppositely disposed ears34 of the lever 32 and an aperture in the head 27. Secured to the eye ofthe cotter pin 33 is the usual ring 35 which is adapted to be engaged bythe hook 17 of the puller member 16. Obviously, upon the energization ofthe electrically controlled apparatus of the device 10, the triggermember 14 and the puller member 16 is actuated in synchronized movementto pull the pin 33, remove the lever 32 and drop the fixture 18, thusset in operation the firing of the cap and the fuse in the detonatorsimultaneously with the dropping of the fixture to test the firing ofthe fuse.

In the function of operation of my improved grenade fuse testingfixture, it will readily be seen that upon the explosion or blast of thefuse, the same will not be confined as in the fixtures heretofore used,but will be permitted to rapidly expand between the screws without anyserious mutilation of the fixture 18 or the screws 26 and ifreplacement, such as additional screws, be required, they are readilyavailable and easily inserted for any distorted or mutilated ones,thereby reducing to a minimum both the time, expense and effort forcontinuous uninterrupted use of the testing device.

In the above description I have described the use of threaded screws inthe fixture 18. However, it will bev understood that simple studs orpins may be inserted in these apertures with transverse smaller pinsextending through the fixtures 18 and the stud retaining them therein ifsuch a construction is so desired.

While in the above specification I have described one embodiment whichmy invention may assume in practice, it will, of course, be understoodthat the same is capable of modification and that such modification maybe made without departing from the spirit and scope of the invention asexpressed in the following claims.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a drop testing device for fuse detonators, a fixed support, afixture releasably mounted in said support for holding a detonator, theexplosive part of said detonator extending upwardly of said fixture, anda plurality of studs on said fixture spaced around the explosive portionof said detonator for guiding said fixture in said support and confiningthe explosion of the detonator when said fixture is dropped.

2. In a drop testing device for fuse detonators, .a fixed support, afixture releasably mounted in said support for holding a detonator, theexplosive part of said detonator extending upwardly of said fixture, aplurality of removable studs on said fixture spaced around the explosiveportion of said detonator for guiding said fixture in said support andconfining the explosion of the detonator when said fixture is dropped.

3. In a drop testing device for fuse detonators, a fixed support, afixture releasably mounted in said support for holding a detonator, theexplosive part of said detonator extending upwardly of said fixture, anda plurality of uniformly spaced apart replaceable studs on said fixturespaced from and parallel to the explosive portion of said detonator forguiding said fixture and confining the explosion of the detonator whensaid fixture is dropped.

4. In a drop testing device for fuse detonator, :a fixed support, afixture releasably retained on said support for holding a detonator, theexplosive part of said detonator extending in a direction away from saidfixture, and a plurality of studs on said fixture spaced around theexplosive portion of said detonator for confining the explosion of thedetonator when said fixture is dropped.

References Cited in the file of this patent UNITED STATES PATENTS2,368,018 Groth et a1. Jan. 23, 1945 2,448,203 Africano Aug. 31, 19482,476,479 Brack July 19, 1949 2,478,659 Jackson et al Aug. 9, 19492,777,323 Street Jan. 15, 1957

